Electrode lines are preferably used to electrically stimulate surrounding body tissue or record electrical signals. They are used in particular also in the region of the coronary vessels or veins in order to control heart contraction. For that purpose, the requirement is that the electrode can be introduced into the selected vessel. That should be implemented with minimum invasion in order to save the patient major stress levels. If the electrode is to be disposed in the coronary sinus at the left atrium or in one of the adjoining veins at the left ventricle, then access takes place in the following fashion: the electrode is firstly passed through a transvenous or venous access, of comparatively large volume, to the right atrium. Thereupon it has to describe virtually a right angle in order to pass into the coronary sinus. If the electrode is to be pushed deeper into the coronary sinus and if further bending movements are to be implemented, a guide wire is provided which provides for displaceability of the electrode. A further requirement lies in steerability of the electrode line in order to guide the electrode line through curved or branched cavities.
U.S. Pat. No. 6,083,170 to Ben-Haim describes a flexible elongate probe having an orientation mechanism which flexes the distal end of the probe in dependence on control signals. Piezoelectric crystals or shape memory alloys are proposed as controllable flexing elements. Electrode lines for the stimulation of tissue, in particular the myocardium, are however intended to be permanently implanted. The control mechanisms which are operated with piezoelectric crystals or shape memory alloys however are usually not sufficiently stable in the long term. The permanently implanted electrodes have to withstand a large number of flexing movements which are caused by variations which are specific to the body, such as for example for the heart beat. In that respect the piezoelectric crystals and shape memory alloys have a tendency to work through the electrode sheath of the electrode line after a certain number of passive flexing movements.
Therefore the object of the present invention is to provide an electrode line of the kind set forth in the opening part of this specification, which can be permanently implanted and which has a suitable control mechanism.